Am I right to say there shouldn't be any directive or <%@ %> tag in the .ascx / user control file? How do I make a db connection on page_load in .ascx and import it to .aspx?

All ASPX, ASCX, ASMX files will have <%@ ... %> at the beginning. This is the directive that tells ASP.Net what that file is, what it's codebehind file is, what class to inherit when it's instantiated. Don't remove it.

"Import" is not quite the correct term. (Depending on what you mean by it.)

If you want to make something publicly accessible in a user control (i.e. visible by the page) then you should use a public property to access it. You could just declare the object as public, but I wouldn't recommend it.

You could do this with a database connection object if you wanted to. You'd should declare the object within the scope of the page (Private m_objDBConn As ...). Then create a public property to access it. Because this is an object, you could make this property read only (as no caller should need to overwrite the object reference, they just want to deal with the object's members).

Public ReadOnly Property DBConnection() As <DBConnectionType>
    Get
        Return m_objDBConn
    End Get
End Property

Are you trying to use this user control simply for the purpose of adding a DBConn to pages that need it? Because that's not really the right application of user controls.

Peter
------------------------------------------------------
Work smarter, not harder.

Ok thanks for the explanation.
I'm not sure of what's the purpose / usage of user control.
Actually what I want to do is as the scenario below:

I wanted develop a database system and we know there must be a connection / comminucation between ASP.Net and our database. And this connection method is always the same, so I would like to create this connection method in a seperate file so that everytime I need the method I can just simlpy "import" (or some other similiar term) the file. One example is as below in ASP

DBConnection.inc
----------------
Dim oConn
Set oConn = Server.CreateObject(ADODB.Connection)
oConn.Open DSN=server

Login.asp
---------

Dim Rs, Query
Query = "Select * From Table1;"
Set Rs = Server.CreateObject(ADODB.Recordset)
Rs.Open Query, oConn

I just want something similiar in ASP.Net, so is there any suggestion or simple example? Thanks again!!

User controls are basically designed so that a web developer can create a composite control to be reused in an application.

Unfortunately, there is no immediately obvious replacement for the classic asp method of an include file that declares a "global" variable such as a db connection so that any page may include it.

A more advanced technique is now available with .Net because of the much better language support in ASP.Net applications. The basic idea is simply to construct a base class that inherits from System.Web.UI.Page. Then you create a Protected property on that class that provide access to your DB connection. In that class you can set up the connection in the Page.Load event handler and close the connection in the Page.UnLoad handler. Then all of your asp.net application's ASPX pages inherit from the base class you created instead of System.Web.UI.Page. This provides them with the standard web form class functionality but also the additions you made.

I have written up a slightly more comprehensive discussion on this idea. You can find it here.

Peter
------------------------------------------------------
Work smarter, not harder.